Chelex® 100 Resin

Overview

Chelex chelating resin is efficiently regenerated in dilute acid and operates in basic, neutral, and weakly acidic solutions of pH 4 or higher. At very low pH, the resin acts as an anion exchanger. This figure shows the zwitterionic forms of the Chelex resin as a function of pH.

The selectivity of Chelex resin for metal cations corresponds to that of iminodiacetic acid. This is a list of selectivity factors for several divalent cations. The selectivity factor is a quantitative measure of the affinity that Chelex resin displays for a particular cation compared to its affinity for a reference cation, in this case Zn+2.

Chelex 100 resin is a styrene divinylbenzene copolymer containing paired iminodiacetate ions, which act as chelating groups in binding polyvalent metal ions. The carboxylic acid groups of Chelex 100 resin classify it as a weak cation exchange resin, but it differs from other exchangers in this class by featuring uniquely high selectivities for metal ions and much higher bond strengths. The resin can be used to ultrapurify buffers and ionic reagents: it will scavenge metal contaminants without altering the concentration of nonmetal ions.

Chelex 100 chelating ion exchange resin has a stronger selectivity for copper, iron, and other heavy metal ions over monovalent cations such as sodium and potassium. Its selectivity for divalent over monovalent ions is approximately 5,000 to 1, and it has a strong attraction for transition metals, even in highly concentrated salt solutions.

Larger volumes and special packaging for industrial applications are available upon request.

Type

Weak cation, chelating

Functional group

R-CH2N(CH2COO-)2

Matrix

Styrene divinylbenzene

Crosslinkage

1%

Approx. MW exclusion

3,500

Operating stability/pH range

4–14/0–14

Min. wet capacity (meq.ml)

0.4

Nominal density

0.65

Ionic forms

Sodium, iron*

* Iron form is glyphosate concentration.

What is the education discount policy?

For more than 15 years, Bio-Rad has made science education a major priority. To support this effort, the company has implemented a discount policy that allows high school and college teaching laboratories to purchase kits, instruments, reagents, and other equipment at preferred prices.

How do I apply for the education discount?

If you are an educator at the high school or college level, visit our Education Discount Policy page to establish an education account number.

If you are placing an order, you may proceed with your order; the account price will be applied if it is lower than the list price. If the problem persists, please call customer service at
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